DE 10 2008 033 304 A1 discloses a vehicle seat with a locking unit. The locking unit, in this case, is fastened on a structural part, in particular a backrest, of the vehicle seat and serves for locking the backrest to a structure of the vehicle, or to the bodywork thereof. To this end, the locking unit comprises a rotary latch which is designated as a pawl and, in the locked state of the locking unit, encompasses a locking bolt which is fastened to the structure of the vehicle.
DE 103 04 574 B4 discloses a locking unit for a vehicle seat. A locking unit of this type includes a pivotably mounted rotary latch for locking with a locking bolt. A latching pawl, which is mounted so as to be pivotable about a different pivot axis, secures the rotary latch in the locked state. A tensioning element exerts a closing torque onto the rotary latch and in this way eliminates any play present between the rotary latch and the locking bolt.
DE 101 26 687 A1 discloses a generic locking unit with a stop element, which defines a receiving opening of a lock housing, and a rotary latch with an extensively constant thickness. In a locked state of the locking unit and with a locking bolt which extends precisely in the axial direction, a first contact region between the locking bolt and the stop element is arranged in the axial direction next to a second contact region between the locking bolt and the rotary latch. The rotary latch, in particular a finger and part of a basic body of the rotary latch, is able to pivot past the stop element.
EP 1 606 484 B1 discloses a locking unit for an engine hood of a motor vehicle having a rotary latch and a stop element on a side plate of a lock housing. The stop element juts outward from the lock housing.
These types of locking units serve, for example, for locking a backrest of a vehicle seat to a seat part and/or to a bodywork or structure of a vehicle or for locking the vehicle seat to the bodywork or structure of the vehicle. Engine hoods, trunk lids or doors of vehicles can also be locked to the bodywork or structure of the vehicle with such locking units.
The locking unit comprises a housing which includes two side plates. In the locked state, the locking bolt fits in a receiving opening of the housing and in a hook aperture of the rotary latch. The rotary latch is an extensively flatly formed component which comprises a material thickness of only a few millimeters.
As a result of tolerances in the vehicle or in the vehicle seat, the locking bolt can become skewed relative to the rotary latch such that the locking bolt is no longer aligned parallel to the rotational axis of the rotary latch, but is at a slant thereto. This can result in noise problems when, for example, the rotary latch is somewhat tilted in its bearing position by the inclined locking bolt and, as a result, comes into contact with the housing. In addition, the skewed position of the rotary latch increases the tensioning distance of the locking bolt. The tensioning distance is the smallest measurement between the support surface of the locking bolt at the receiving opening of the housing, on the one hand, and the oppositely situated support surface of the locking bolt at the hook aperture of the rotary latch on the other hand. In the tolerance-free case, where the bolt cross section is circular and support surfaces are arranged distributed about 180° over the bolt circumference between, on the one hand, the locking bolt and the receiving opening of the housing and, on the other hand, the locking bolt and the hook aperture of the rotary latch, the tensioning distance is equal the bolt diameter.
An increase in the tensioning distance results in a play-free position that is provided in the locking unit only having a limited effect as the rotary latch is not able to rotate far enough in the direction of its locking position. Where there is a severe increase in the tensioning distance, the latching pawl is not able to drop in or is not able to drop in completely. The rotary latch is not then secured in the locked state. In addition, the skewed position of the locking bolt results in a loss of overlap between the rotary latch and the latching pawl, which can reduce the strength of the locking unit.